Thermostatic circuit-controller.



PATBNTED AUG. s, 1905.

H. A. FISKE THERMOSTATIG CIRCUIT GONTRQLLER.

APPLICATION FILED NOV. 10,1903.

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UNITED sTATEs NPATENT oEEioE.

HENRY A. FISKE, OF NEWTON, MASSACHUSETTS, ASSIGNOR TO EASTERN FIREPROTECTION COMPANY, A CORPORATION OF MAINE.

THERNIQSTATIC CIRCUIT-CONTRCLLER.

Specification of Letters Patent.

.Patented Aug. 8, 1905.

Application filed November 16, 1903. Serial No. 181,269.

To all whom, it may con/cern:

Be it known that I, HENRY A. FISKE, a citi- Zen of the United States,and a resident of Newton, in the county of Middlesex and State ofMassachusetts, have invented new and useful Improvements in ThermostaticCircuit- Controllers, of which the following is a specification. Y

My invention relates to thermostatic devices for controlling anelectriccircuit, and is herein.

' and practical device of this character which will be more sensitiveand certain in operation than those heretofore used.

My device in its preferred form is illustrated in the accompanying'drawings, in which.-

Figure 1 is a side elevation of the complete deviceas applied to aportion of a journalbearing. Fig. 2 is a central vertical sectionthrough the device shown in Fig. 1 detached.

Figs. 3 and 4 are horizontal sections taken,

respectively, on the lines 3 3 and 4 4 in Fig. 2. Fig. 5 is a sectionsimilar'to Fig. 2, but showing a slight modification.

The working parts of my device are preferably inclosed in a casingcomprising a metallic cup-shaped body portion 2 and a removable cover3,provded with a perforation 4,through which the insulated circuit-wires5 5 are led from the interior of the device to the alarmcircuit. Thebody portion 2 is usually made cylindrical in order that the device maybe applied to a journalbearing 6 by drilling a hole in the bearing andinserting said body portion into it, as shown in Fig. 1.

Within the upper part of the body portion 2 is located an insulatingdisk or plug 7 ,from the bottom face of which project two metalliccontact-terminals 8 8, with their lower ends reaching nearly to thebottom of said body portion.

`These terminals 8 8 are insulated from one another by a slab 9 of hardrubber,vulcanized fiber, or the like, and said terminals and slab,

taken collectively, are preferably turned to cylindrical shape, as shownin Figs. 3 and 4, and their upper ends are inserted tightly into a holeformed in the plug 7, whereby they are held in proper relation to oneanother and to the body portion 2 atthe center of the latter. Thecircuitwires 5 pass through the top of the plug7 and their bared ends 10are inserted, respectively, into holes drilled in the upper ends of theterminals 8 8, to which said ends are soldered. The lower ends of theterminals 8 8 and the slab 9, taken collectively. are preferably reducedin diameter, as shown in Fig. 4, and at the bottom of the body portion 2is located a ring 11, of fusible conducting material, such as thefusible solder commonly used in thermostats, this ring being of suchsize as to fit the lower end of the body portion 2 and having itscentral opening large enough to receive the lower ends of thecontact-terminals 8 8 without touching the same. Just above the ring 11is located a ring 12, made of material which is an insulator andpreferably a poor conductor of heat. As shown `in Fig. 2, this ring 12is adapted to move freely in a vertical direction within the bodyportion 2 and around the reduced portion of the terminals 8 8 and slab9, and a coiled spring 13, normally in a state of compression, isinterposed between the ring 12 and the plug 7. As thus constructed, whenthe temperature of the bearing into which the device is inserted reachesthe predetermined meltingpoint of the fusible solder employed the ring11 is melted and the solder of which it is composed is forced downwardand caused to flow laterally by the 'actionV of the ring 12 and spring13, and is thus brought into contact with the lower ends of theterminals 8 8 and completes the alarm-circuit through these terminals.The body portion 2 is shown as provided near -its lower end with aninwardlyextending annular shoulder 14, which act-s as a stop to receivethe ring 12 when forced downward, and thus prevents any tendency toforce the melted solder upward between said ring and the body portion 2or otherwise remove it from contact with the terminals 8 8. The spacebeneath the shoulder 14 should be so proportioned as to equal the volumeof the solder contained in the ring 11.

In Fig. 5 the ring 12' is shown as making a closerlit with the bodyportion 2 and with the terminals 8 8 and slab 9, the spring 18 beingomitted. Otherwise this modification of my device has the sameconstruction as is shown in Fig. 2, and in this case when the ring 11melts the solder is caused to iiow into contact with the terminals 8 8by gravity only. The operation of the arrangement shown in Fig'. 1 is,in effect, independent of gravity, so that the device may be located inany desired position. W'ith either arrangement, however, the ring,` 12or 12 performs the desirable function of a heat-insulating backing,which prevents heat from escaping or radiating' upward from the ring;11, thus promoting' the sensitiveness and certainty of operation of thedevice. Said ring' also serves to prevent any possibility of lateralmovement of the contactterrninals which might bring' them into contactwith the solder ring 11. I consider the employment of the solder in theform of a ring, in connection with the retaining-receptacle whichincloses it, to be one of the features of my invention, because it isthereby prevented from becoming displaced and brought into accidentalcontact with the terminals 8 8, and it is also equally exposed in alldirections to the flow of hcatfrom the journal-bearing. Furthermore,when it melts the tendency of the melted solder is necessarily to fiowtoward the open center of the ring', so that it must instantly makecontact with the terminals 8 8 and cannot flow around or toA one side ofthe same. It will be evident that the metallic body portion 2 is itselfcapable of serving` as one of the contact-terminals in case the machineto which my device is attached is included in the alarm-circuit and thatthe device may be modified in various other ways without departing' frommy invention.

I claim as my invention-- 1. In a thermostatic circuit-controllingdevice, the combination of a cup-shaped body portion, providing' asolder-retaining receptacle, a ring of fusible solder contained thereinand located adjacent to the walls thereof, and circuit-terminals locatedat the interior of said ring' in position to be electrically connectedby contact with said solder when melted, substantially as set forth.

2. In a thermostatic circuit-controlling` dei circuit, and a ring' offusible solder surrounding; said terminals and located adjacent to thewalls of the body portion, substantially as set forth.

4. In a thermostatic circuit-controlling' device, the combination of acup-shaped body portion, insulated contact-terminals contained thereinand adapted to be included in an alarmcircuit, a ring' of fusible soldersurrounding' said terminals, and an insulating-ringl covering saidsolder ring.

5. In a thermostatic circuit-controlling,` device, the combination of acup-shapcd body portion, insulated contact-terminals contained thereinand adapted to be included in an alarmcircuit, a ring of fusiblesoldersurrounding' said terminals, a supplementary ring in contact withsaid fusible ring', and a spring tending' to press said rings together.

6. In a thermostatic circuit-controlling device, the combination of acup-shaped body portion, an insulating-plugV contained therein, twocontact-terminals adapted to be included in an alarm-circuit and a slabinsulating said terminals from each other, said terminals and slabhaving', taken collectively, a cylindrical form and being' held in ahole formed in said plug, and a mass of fusible solder located adjacentto said terminals but normally out of contact therewith.

7. In a thermostatic circuit-controlling dcvice, the combination of acup-shaped body portion, containing' an insulating-plugl T,contact-terminals 8 8 carried by said plug and projecting from the lowerside thereof, circuit-wires 5 5 connected to said terminalsrespectively, an insulating-slab 9 located bctween said terminals, aring` 12 surrounding' said terminals near their lower ends, and a ring'of fusible solder conlined between said ring' 12 and the bottom of thebody portion, substantially as described.

8. In a thermostatic circuit-controlling.;l device, the combination of abody portion 2, plug' 7,contactterminals 8 8, insulating-slab 9,circuit-wires 5 5, fusible ring' 11, insulating'- ring 12, and spring13, substantially as described.

9. In a thermostatic ciremt-controllingl device, the combination of abody portion 2, plug' 7,.contact-terminals 8 S, insulating-slal.) 9,circuit-wires 5 5, fusible ring 11, insulating-ring' 12, spring' 13 andshoulder 14, substantially as described.

In testimony whereof I have hereunto subscribed my name this 22d day ofOctober, 1903.

HENRY A. FISKE.

l/Vitnesses:

E. D. CHADWIOK, Josera T. BRENNAN.

